Cryptophytes are unicellular, eukaryotic microalgae that are ubiquitous in freshwater, estuarine, and marine environments. Part of their ecological success is due to their cryptophyte phycobiliprotein (Cr-PBP) accessory pigments that capture wavelengths of light that are not efficiently absorbed by chlorophylls, thus allowing them to occupy distinct vertical niches in the water column. There are nine defined Cr-PBP types, named for their wavelength of maximal absorbance, that are responsible for wide differences in color among cryptophyte species. Yet, very little tis known about how spectral absorption characteristics of Cr-PBPs vary among species. In their latest study titled "Variability in spectral absorption within cryptophyte phycobiliprotein types", Drs. Kristiaan Merritt and Tammi Richardson investigated variability in primary and secondary peak absorbance wavelengths and full width at half max (FWHM) values of spectra of Cr-PBPs extracted from 75 cryptophyte strains (55 species) grown under full spectrum irradiance. They discovered that there may be substantial differences in spectral shapes within Cr-PBP types, and provide additional criteria for classification in cases where the wavelength of maximum absorbance alone is not definitive. Thus, variations in spectral characteristics among strains containing the same presumed Cr-PBP type may indicate differing chromophore composition and/or the presence of more than one Cr-PBP in a single cryptophyte species.